Univ. of Pittsburgh to lead international trial for vocal cord paralysis and paresis

03/22/04

Study is the largest study in voice disorders

PITTSBURGH, March 22 – Researchers at the University of Pittsburgh have designed and are now participating in a large multi-site prospective clinical trial to gauge the effectiveness of calcium hydroxylapatite (CaHA) injections in patients with vocal cord paralysis, atrophy or paresis. The study, which will be conducted at 15 international sites, is the largest such trial in the field of voice disorders.

In the study, patients will receive injections of CaHA, an FDA-approved implant composed of calcium phosphate, into the injured vocal cord. At follow-up visits at one, three, six and 12 months, researchers will measure the effectiveness of the injections.

"In this study, we are trying to determine the long-term efficacy and utility of CaHA as an injection material to treat vocal fold disorders," said Clark Rosen, M.D., associate professor of otolaryngology at the University of Pittsburgh School of Medicine and director of the University of Pittsburgh Voice Center. "Current injection materials have limitations in terms of their effectiveness and longevity; there are concerns with some of the substances being reabsorbed and other materials triggering a rejection response to the material. It is hoped that the CaHA injection material will be an improvement over presently available substances."

In vocal cord disorders such as paralysis, atrophy and paresis, one or both vocal cords are weakened and lack the ability to close and thus vibrate properly, resulting in a soft, breathy or weak voice. The affected (injured) cord may also allow food and liquids into the trachea or lungs causing difficulty with swallowing and coughing.

Often vocal cord disorders may not heal without treatment. Standard treatments include voice therapy and surgery. In surgery, doctors attempt to add bulk to the injured vocal cord by injecting a substance, most commonly Teflon, fat or collagen into the cord. This moves the injured cord closer to the non-injured cord, allowing for better contact and improved speech and swallowing.

Vocal cord paralysis may be caused by chest and neck surgery, brain injury, neck injury, lung or thyroid cancer, certain neurologic conditions, a tumor pressing on a nerve, or a viral infection. In older people, vocal cord atrophy is a common problem affecting voice production.

CaHA is a form of calcium phosphate present in bones and teeth, and has been used for bone replacement. CaHA acts as scaffolding for soft tissue ingrowth with the calcium/phosphate particles providing a strong, long-lasting foundation that allows local cellular infiltration. The resulting structure of CaHA and natural tissue forms a cohesive implant that remains in place to provide long lasting durable reinforcement of soft tissue. The CaHA injection material is FDA approved for vocal cord augmentation.

Results from a pilot study from the University of Pittsburgh Voice Center will be published in the Journal of Voice in June.